GEOFF BENNETT: Meantime, tens of billions of dollars in military assistance for Israel and Ukraine and money for the U.S. Southern border remain stalled on Capitol Hill.

For the White House perspective, I spoke with National Security Adviser Jake Sullivan earlier this evening.

Jake Sullivan, welcome back to the "NewsHour."

JAKE SULLIVAN, U.S. National Security Adviser: Thanks for having me, Geoff.

GEOFF BENNETT: The administration is delivering a clear warning that, without congressional action by the end of the year, resources will run out for the U.S. to provide Ukraine with the weapons and equipment it needs.

Practically, what would that mean for Ukraine on the battlefield?

JAKE SULLIVAN: Well, what it would mean, Geoff, is that we would no longer be able to supply Ukraine with the artillery ammunition they need to hold their lines against Russian advances and to help them advance themselves to deoccupy territory Russia has taken.

It would mean that we would no longer be able to provide interceptors for Ukraine's air defense systems, which are protecting their soldiers on the front lines and, even more importantly, are protecting their cities from attacks by Russia that are trying to plunge the country into cold and darkness by destroying the electricity grid.

So these are the kinds of practical results that would happen if we do not continue to provide funding to Ukraine.

And Vladimir Putin is counting on this.

In fact, he said that if the United States stops giving money to Ukraine and the rest of the world stops giving money to Ukraine -- quote -- "Ukraine would have one week to live."

We need to prove Vladimir Putin wrong.

We need to get the funding to Ukraine so they can bravely and courageously continue to defend their country against Russian aggression.

GEOFF BENNETT: The U.S. has already contributed well over $100 billion to Ukraine's war efforts since Putin invaded that country back in February of 2022.

Beyond the funding, how can the U.S. better enable and empower Ukraine to actually breach Russian defenses and win the war, instead of sustaining their current fight?

JAKE SULLIVAN: Well, we have to take a step back.

When this war started in February of 2022, the experts were predicting that Ukraine would fall in a week, that the capital of Ukraine, Kyiv, would be under a Russian flag.

Today, Kyiv stands, and Ukraine stands as a sovereign independent country because of the funding that we have provided to Ukraine.

And more than that, since Russia launched its offensive in the early months following the invasion, Ukraine has taken back more than half the territory that Russia has occupied, more than 50 percent of that territory.

And that is thanks first to the bravery of the Russian -- of the -- excuse me -- Ukrainian forces, but second to the arms and supplies that the United States and the international coalition has provided to them.

So, if we can sustain those supplies, if we can continue to support Ukraine, it can continue to make progress on the battlefield and, equally importantly, it can continue to resist efforts by Russia, continuing efforts, to take more Ukrainian territory.

And that is basically fundamentally in the interests of the United States, because if, Russia succeeds in this fight against Ukraine, all of Europe is at risk.

And history tells us that, when all of Europe is at risk, the United States will pay a lot more later than the sums we are paying today to support Ukraine in this fight.

GEOFF BENNETT: House Speaker Mike Johnson says there will be no additional funding for Ukraine without first making extensive reforms to the U.S. immigration system.

And it was the White House, not Republicans, who initially linked funding for Israel, funding for Ukraine, money for Taiwan, and border security.

Why are the Republicans' border demands now a nonstarter?

JAKE SULLIVAN: Well, you make a very good point, Geoff.

It was, in fact, President Biden who put forward a supplemental funding request that included a substantial amount of funding for the border to enable us to have an effective and humane border security policy.

And that should have bipartisan support.

Democrats and Republicans should be able to come together around commonsense measures to ensure that our border policy is rational, effective and humane.

Democrats are ready to do that.

It turns out that what the Republicans are putting forward is to take-it-or-leave-it proposition.

They are not prepared to have a serious discussion at this time -- hopefully, that will change -- about border policy.

And as a result, they're holding Ukraine funding hostage to their demands on the border.

Our view is that it is in America's core national security interests to fund Ukraine against Putin, against Russian aggression.

And we can work together on the border.

But Ukraine should not be held hostage to the border.

That would be a grave mistake for our own national security and for broader global stability.

GEOFF BENNETT: On the Israel-Hamas war, the World Health Organization, the representative in Gaza said the humanitarian situation is getting worse by the hour, with intensified bombing and Khan Yunis and in Rafah.

A spokesperson for UNICEF said there is nowhere for civilians to go.

"Nowhere is safe," that was the quote.

In the administration's view, is Israel heeding the administration's insistence to limit civilian suffering in the southern part of Gaza?

JAKE SULLIVAN: Well, Geoff, what the Israeli Defense Forces has done in the last couple of days is highly unusual.

They have actually identified the specific areas of this city in the south, Khan Yunis, that they intend to conduct ground operations in and asked civilians to leave.

They have asked them to leave those areas.

So, in a sense, they telegraphed their punches where they were going to conduct their military operations.

Outside of those areas, we have made the case to Israel that it is critical that we get humanitarian assistance to Palestinian people who have been displaced because of the fighting, that they get shelter, food, water, medicine as necessary.

And over the course of the past days, we have seen a flow of humanitarian assistance coming in through that border crossing in Egypt.

We would like to see more.

There needs to be more aid that comes in, and Israel needs to take every possible care in the world to distinguish between legitimate targets, Hamas terrorists, who they are going after, and Palestinian civilians, who deserve to be protected, whose lives should have the same sacred quality that every life, every innocent life around the world has.

And we have made that case relentlessly to our Israeli counterparts, both publicly and privately, over the last many weeks.

GEOFF BENNETT: What is the U.S. prepared to do if it determines that Israel is not following a specific plan to mitigate civilian casualties?

JAKE SULLIVAN: Well, instead of trying to answer an if-then question, what I would just describe is what we do every day, what I did today.

I was on the phone for more than an hour with one of my Israeli counterparts walking through practical measures, like how to get more fuel in to power sanitation, desalinization, bakeries, so that people can eat and get potable water.

I talked about the steps that Israel could take to reduce the potential for civilian casualties, particularly in these safe areas outside of active combat hostilities.

We're going to continue to do that, and we're going to continue to expect that Israel meet the basic standards of international humanitarian law, and we will state our principles clearly and directly, as President Biden has done since the earliest days.

But at the same time, we are also going to support Israel as it goes against those terrorist masterminds who authored the worst massacre of Jews since the Holocaust on October 7.

And we cannot forget that Hamas is, even as we speak today, continuing to fire rockets and missiles against innocent civilians in Israel and represents a continuing threat that any country, including Israel, would have the right to go after.

GEOFF BENNETT: Is there any semblance of a path or a timeline to resume the talks for another temporary cease-fire?

JAKE SULLIVAN: Unfortunately, Geoff, there's not a specific timeline.

And the reason for that is because Hamas did not follow through on its end of the bargain.

It said that it was going to release the women and children that it was holding.

And it is still to this day holding civilian women who it refuses to release.

And we don't know why it refuses to release them.

But Israel is not prepared to move forward and leave those women behind.

And so Hamas chose not to release them, and that meant the end of the pause.

The ball is in Hamas' court.

It could release those women, and then Israel has made clear it is prepared to move on to additional negotiations to deal with other hostages as well.

And we, the United States, are determined not to rest.

We will be relentless until we ensure that every American hostage being held is safely reunited with their family.

GEOFF BENNETT: National Security Adviser Jake Sullivan.

Jake, thanks for your time this evening.

JAKE SULLIVAN: Thanks.